Sebastian Weingärtner

Accuracy, Precision, and Reproducibility of Four T1 Mapping Sequences: A Head-to-Head Comparison of MOLLI, ShMOLLI, SASHA, and SAPPHIRE

PURPOSE To compare accuracy, precision, and reproducibility of four commonly used myocardial T1 mapping sequences: modified Look-Locker inversion recovery (MOLLI), shortened MOLLI (ShMOLLI), saturation recovery single-shot acquisition (SASHA), and saturation pulse prepared heart rate independent inversion recovery (SAPPHIRE). MATERIALS AND METHODS This HIPAA-compliant study was approved by the institutional review board. All subjects provided written informed consent. Accuracy, precision, and reproducibility of the four T1 mapping sequences were first compared in phantom experiments. In vivo analysis was performed in seven healthy subjects (mean age ± standard deviation, 38 years ± 19; four men, three women) who were imaged twice on two separate days. In vivo reproducibility of native T1 mapping and extracellular volume (ECV) were measured. Differences between the sequences were assessed by using Kruskal-Wallis and Wilcoxon rank sum tests (phantom data) and mixed-effect models (in vivo data). RESULTS T1 mapping accuracy in phantoms was lower with ShMOLLI (62 msec) and MOLLI (44 msec) than with SASHA (13 msec; P < .05) and SAPPHIRE (12 msec; P < .05). MOLLI had similar precision to ShMOLLI (4.0 msec vs 5.6 msec; P = .07) but higher precision than SAPPHIRE (6.8 msec; P = .002) and SASHA (8.7 msec; P < .001). All sequences had similar reproducibility in phantoms (P = .1). The four sequences had similar in vivo reproducibility for native T1 mapping (∼25-50 msec; P > .05) and ECV quantification (∼0.01-0.02; P > .05). CONCLUSION SASHA and SAPPHIRE yield higher accuracy, lower precision, and similar reproducibility compared with MOLLI and ShMOLLI for T1 measurement. Different sequences yield different ECV values; however, all sequences have similar reproducibility for ECV quantification.

Combined saturation/inversion recovery sequences for improved evaluation of scar and diffuse fibrosis in patients with arrhythmia or heart rate variability.

To develop arrhythmia‐insensitive inversion recovery sequences for improved visualization of myocardial scar and quantification of diffuse fibrosis.

Adaptive registration of varying contrast-weighted images for improved tissue characterization (ARCTIC): Application to T1 mapping

To propose and evaluate a novel nonrigid image registration approach for improved myocardial T1 mapping.

Free-breathing multislice native myocardial T1 mapping using the slice-interleaved T1 (STONE) sequence.

To develop a novel pulse sequence for free‐breathing, multislice, native myocardial T1 mapping.

Improved quantitative myocardial T2 mapping: Impact of the fitting model

To develop an improved T2 prepared (T2prep) balanced steady‐state free‐precession (bSSFP) sequence and signal relaxation curve fitting method for myocardial T2 mapping.

Free-breathing post-contrast three-dimensional T1 mapping: Volumetric assessment of myocardial T1 values

To develop a three‐dimensional (3D) free‐breathing myocardial T1 mapping sequence for assessment of left ventricle diffuse fibrosis after contrast administration.

Free-breathing combined three-dimensional phase sensitive late gadolinium enhancement and T1 mapping for myocardial tissue characterization

To develop a novel MR sequence for combined three‐dimensional (3D) phase‐sensitive (PS) late gadolinium enhancement (LGE) and T1 mapping to allow for simultaneous assessment of focal and diffuse myocardial fibrosis.

On the selection of sampling points for myocardial T1 mapping

To provide a method for the optimal selection of sampling points for myocardial T1 mapping, and to evaluate how this selection affects the precision.

Joint myocardial T1 and T2 mapping using a combination of saturation recovery and T2-preparation

To develop a heart‐rate independent breath‐held joint T1–T2 mapping sequence for accurate simultaneous estimation of coregistered myocardial T1 and T2 maps.

Magnetic resonance fingerprinting using echo-planar imaging: Joint quantification of T1 and T2∗ relaxation times

To develop an implementation of the magnetic resonance fingerprinting (MRF) paradigm for quantitative imaging using echo‐planar imaging (EPI) for simultaneous assessment of T1 and T2∗ .